Sealed switch relay



March 8, 1966 J. N. PEARSE SEALED SWITCH RELAY 2 Sheets-Sheet l Filed July 23, 1962 MyW/XMIM AT TORNEY 0 0 0 o o o 0 0 0 3 2 l.

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INVENTOR JAMES N- PEARSE ATTORNEY lsloo J. N. PEARSE SEALED SWITCH RELAY FIELD INTENSITY IN OERSTEDS DUE TO RMANENT MAGNET AMPEFIE TURNS March 8, 1966 Filed July 25, 1962 United States Patent O 3,239,626 SEALED SWITCH RELAY James N. Pearse, Milwaukee, Wis., assigner to Allen- Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Filed July 23, 1962, Ser. No. 211,628 S Claims. (Cl. u-87) The present invention relates to relays and components thereof, and particularly to relays incorporating sealed reed switching units and to a method of manufacturing said relays.

A principal object of the present invention is to provide an electromagnetic relay including a plurality of commingled sealed reed switching units actuated by a common coil, and wherein the operating characteristics of one unit will in no manner interfere with the operating characteristics of adjacent or otherwise proximately disposedV switching units, such units being selected from type having operating characteristics, such as normallyopen, normally-closed, normally-closed contacts selectively responsive to (-1-) or currents, latching contacts that latch with (-1-) or currents and unlatch with or (-1-) currents, respectively, and paired latching contacts having one switching member latching on (-1-) and unlatching on current and the other member of the pair latching on and unlatching on (-1-) current, and wherein only one biasing magnet is required for a respective pair of latching switches.

A corollary object of the present invention lies in the provision of sealed reed contacts disposed in the same relay coil in close proximity with one another, and wherein certain of said contacts are operated as magnetically biased, normally-closedV contacts, and being so arranged as to not affect the operation of the normallyopen or weakly biased latching switches disposed in the vicinity thereof.

It is a further object of the present invention to pro vide la relay construction utilizing sealed reed switching units wherein latching contacts may be provided in the same relay with normally-open and normallyclosed contacts.

It is still another object of the present invention to provide means for adjusting the strength of a bias magnet used in conjunction with the normally-closed reed switching unit or with the latching switching units without altering the physical shape of the magnet or its proximity to the switch, thereby allowing means for compensating for variation in the reed switch operate characteristics and geometry within the relay coil to re-open at some bucking flux by the relay coil that is specified as a relay parameter.

It is a still further object of the present invention to provide a method of manufacturing an electromagnetically operated relay utilizing sealed switching units, wherein the switching units :are pre-selected for their individual operate and release characteristics and are thereafter arranged in a prescribed relationship to one another and to a magnetic coil to take advantage of the variations in intensity of flux induced by the coil andV influencing the operation of the various switching units operated thereby, and wherein such pre-selection and arranging will 'further tend to permit the various switching units to operate or to release in unison.

The present invention disclosed herein finds application in relays of the type comprising a plurality of glass-sealed reed contact devices arranged co-extensively in a group with a common coil surrounding the same, which coil serves to simultaneously energize the reeds to control electrical circuits. A iluX-carrying metallic casing substantially surrounds the coil as :a means of directing the coil flux towards the reed switches. The reeds of such ICC relays are also of known construction and are made of magnetic material of high electrical conductivity and may be plated with gold or other precious metal, if so desired. The contacts of each reed switch are preferably enclosed in an hermetcally sealed, tubular envelope made of vitreous material such as glass. The envelope is filled with an inert gas such as helium, argon, neon or other non-corrosive gas and is sealed at each end to prevent escape of the gas and admission of foreign particles to the contact areas.

For a fuller understanding of the nature and objects of this invention, reference should be had to the following detailed description taken in connection with the accompanying drawings, in which:

FIG..l is a view in longitudinal section taken in the plane of lines 1-1 of FIG. 2 of a relay embodying the features of the present invention;

FIG. 2 is a cross-sectional View taken in the plane of lines 2 2 of FIG. l;

FIG. 3 isa top plan view of a biasing magnet used with certain of the switching units which may be used with the relay of the present invention;

FIG. 4 is a view in side elevation of the biasing magnet of FIG. 3, and indicating the flux path through an adjacent normally-closed or latched contact;

FIG. 5 is a diagrammatic View, partially in section of the apparatus in magnetizing the biasing magnet of FIG. 3;

FIG. 6 is a diagram of the demagnetization curves of `ferrite material useful in manufacturing the biasing magnet of FIGS. 3 and 4;

FIG. 7 is a diagram of a typical set of curves illustrating the range of ampere-turns needed to operate and to release a typical group of normally-closed switches used in conjunction with the relay of this invention.

It is to be noted that in the views of FIGS. l, 2 and 5 that various supporting members not lforming a specic part of the present invention have been omitted for the sake o-f clarity in drawing and description. It will be obvious that additional supporting spacer members, terminals and other necessary appurtenances will be required in the commercial application of the relay of FIGS. l and 2. Stationary supporting members and other means of support are also required in the magnetizing apparatus of FIG. 5, but have also been eliminated for the sake of clarity and will be readily understood by those familiar with the art.

It has been observed that in the magnetic circuit of a relay coil there is considerable variation in the usable iluX density affecting operation of the various switching units actuated by the coil. That is, the magnetic eld is known to be strongest at each of the corners of the rectangularly wound coil, and is somewhat lessened at leg portions intermediate these corners, whereas the magnetic eld affecting the operation of switching units disposed centrally of a coil window is even of relatively lesser intensity than that of the intermediate leg portions. It will be further appreciated that normal manufacturing procedures inevitably produce some variations in the switch operating characteristics. Tolerance limitations are difficult to maintain and changes in the unit cannot be made after sealing. This will be apparent from the following description of the various switching units, designated generally by the reference numeral 10 (see FIGS. 1 and 2) and disposed in the window 11 of the coil 12. The switches 10 each comprise two yelongated metal strips or reeds 13 and 14 sealed in a glass tubular enclosure 15. The strips are of ferromagnetic, electrically conducting metal, preferably of a nickel-iron alloy having a coeicient of expansion approximately equal to that of the glass enclosure 15, and terminate in overlapping contact surfaces 16. The contact surfaces 16 may be coated with gold or other precious metal, if so desired. The interior 17 of the glass enclosure is preferably filled with an inert gas to minimize contact contamination and deterioration through corrosion, etc. The space between the contacts 16 is quite minute and may be between 2 and 3 millimeters. Each metallic reed 13, 14 is anchored in the glass enclosure at 18. The switching units 10 are manufactured as normally-open contacts, as shown in the units of the columns designated X and Y of the view of FIG. 2. Application of a magnetic field from the coil 12 causes the reeds to assume a position parallel with the magnetic lines of force, thereby contacting each other.

A metallic flux-carrying casing 19 surrounds the coil 12. The casing 19 being of low reluctance, prevents the loss of ux through other undesired paths and hence substantially all of the coil iiux is directed to, and concentrated at the gaps between the overlapped portions of the reeds 13 and 1d.

It is often desirable, however, to provide normallyclosed contacts or biased closed latching contacts as shown in the switching units 10 of the columns designated by the reference character W of FIG. 2. Here a biasing magnet, indicated generally by the reference numeral 20, is provided to maintain the contacts in the normally-closed position. In the case of latching contacts AW and BW (see FIG. 2), these contacts are normally open, as shown, but remain latched upon the iirst pulse of current of the proper direction in the coil 12, as will be later explained. The magnet 20 is provided with a keeper 21 of magnetic material. The magnet 20 and its manufacture form a part of the present invention which will be hereinafter described.

It is also often desirable to provide paired latching contacts composed of adjacent switches, indicated as switching units 10 of rows Y and Z of FIG. 2. In this case a magnet 22, without keeper is disposed between a pair of switching units 10, as may be found in rows designated by the reference characters A, B, C, D of columns Y and Z of FIG. 2.

In the present embodiment, as aforementioned there may be single and paired latching contacts. The action of the relay with respect to the latching contacts, in general, can be visualized by considering the directions of the magnetic fields produced by the permanent magnets 20 or 22, respectively, in conjunction with the coil 12. An otherwise normally-open switch, such as the switches AW and BW, is subject to the inuence of an adjacently disposed permanent magnet, but the force of the magnet is maintained at a level not high enough to close the switch contacts. If, however, a pulse of current is sent through the coil 12, which sets up a flux in the same direction as the flux from the permanent magnet, the contacts will close. The permanent magnet, the contacts will close. The permanent magnet then keeps them closed with no further current required in the coil. To open the contacts, a second pulse of current is sent through the coil in the opposite direction and it produces a flux that opposes and overcomes the permanent magnet flux, thus releasing the reeds.

In the case of the paired latching contacts, such as those of columns Y and Z of FIG. 2, the switching units 10 are alternatively operated relative to one another, and are illustrated in a normal or initial position with the contacts AY, BY, CY and DY open and the other respective pairs AZ, BZ, CZ and DZ in latched closed position. Thus, for instance, upon supplying the coil 12 with a charge of current the contacts AZ, BZ, CZ and DZ will unlatch and their paired contacts AY, BY, CY and DY will latch closed. Reversal of supply current to current will return the contacts to the respective normal positions illustrated.

Having now outlined and described the various components which may be used to make up a relay, it will be apparent that heretofore a commingling of switching units has been next to impossible to provide in one coil, and

only then where provision was made for considerable spacing between each of the switching units to avoid the problem of having the operation of one unit affect the operation of a unit of differing magnetic characteristics. The present invention contemplates and overcomes these problems, and further provides a relay construction which, at the same time, meets rigid industrial specifications, requiring that each of the switching units of the relay operate at of nominal voltage at its highest expected operating temperature. For example, under these conditions, all switches are expected to operate or release at or below a given voltage at minimum coil power. For instance, the 80% value of a 24 volt coil; i.e., 19.2 volts, will be reduced, for commerical application to a value of under 15 volts at a operating maximum temperature of C. I-Ieretofore, in order to manufacture each of the switches to meet such severe requirements, rigid tolerances were maintained, leading to considerable scrapping of switches. The problems will become particularly apparent when one realizes that there is no means possible for adjustment after the reeds 13 and 14 have once been sealed in the tubes 15. However, the present invention contemplates the fact that coils vary in flux density at certain areas of the coil configuration, and takes advantage of this fact in providing a relay wherein each contact is disposed in optimum operating position relative to the field intensity of the coil.

In accordance with this discovery, each of the switching units 10 are made in accordance with best known Amanufacturing techniques, with relatively broad and reasonable tolerances. The switches are then sorted, selected and placed into groupings according to the number of ampere-turns required to operate the contacts to closed positions and to release the contacts to open position. 'That is, a standard test coil is provided for sorting purposes (not shown). This test coil consists of 10,000 turns of No. 36 Wire and is 1% inches long. Thus, for instance, each of the switching units 10 may be taken from the manufacuring line and placed in the standard coil for measurement of its operate and release characteristics. Thereafter, the switches `10 .are sorted into containers for proper selection. The switching units 10, designated by column and rows AW, DW, AZ and DZ of FIG. 2, are disposed in areas of relatively high flux density. For instance, a typical 24 volt relay may be built to comprise switching units sorted into a range of 94-101 ampere-turns to operate the contacts from normallyopen to closed position, whereas release of the contacts will fall within `a range of 38-43 ampere-turns for the same switch. The intermediately disposed switching units of column-rows AX, AY, DX, DY, BW, CW, BZ and CZ requiring greater amounts of ux, may be selected from those sorted into an operate `ampere-turn range of 86-93 and release ampere-tum range of 32-37. The more remotely disposed switching units 10 of columnrows BX, BY, CX and CY would be chosen to operate at 78-85 ampere-turns and to release at 26-31 ampereturns.

Thus, the relative sensitivity of each of these switches w-ill be disposed in positions of higher flux density of the coil and the relay will end up with all of its switching units 10 operating and releasing at within an approximate 15 volt range at Iminimum coil power, and thereby fit within the industrial specifications in one commingled unit. In addition, another major advantage in providing the present construction lies in the fact that all switching units atfected by the coil 12 will operate substantially in unison. It will be apparent that the disposition of the switching units in accordance with a preselected operating range is of a considerable meritorious contribution when one considers the relative dithculty in manufacturing the present type of switching units and the rigid tolerances that have been required previously.

Another important feature of the present invention resides in the novel biasing magnets and 22 used in the normally-closed switching units C and D of column W of FIG. 2, and in the latching switching units of A and B of column W, and the paired latching units of columns Y and Z of FIG. 2.

Although it is possible to use other magnets, it has been found to be preferable to provide a ceramic magnet of barium ferrite for biasing the reeds 13 -and 14 into closed position `or for use as a magnetic latch. The characteristics of this ceramic permanent magnet material is that its retentivity is high, and if subjected to a demagnetizing field, it will substantially regain its original magnetic characteristics when the demagnetizing field disappears. The permeability of the ceramic permanent magnet material is very close to unity. Therefore, it is like air and cannot be saturated. In addition, one very important feature is that its field is directional in nature. The magnet 20 is illustrated in the views of FIGS. 3 and 4, and is further provided with a keeper 21 which insures the directional characteristics in the case of normally-closed or latched switches of column W of FIG.2. The magnet 22 is used without .a keeper for latching purposes, when one magnet is intended to affect the operate or release characteristics of paired latching switches, such asthose of columns Y and Z of FIG. 2.

`a high coercive force, as shown by the demagnetization curve 25 of the second quadrant of the B-H hysteresis loop of FIG. 6, as well as ya low residual induction. The preferred ceramic magnet is of the non-oriented type, but it is within the province of the present invention to utilize oriented barium ferrite magnets, provided that the -field influencing the magnet is maintained so that the induction B is above the knee of the curve 26 of FIG. 6. The advantage of using the non-oriented material will be apparent from' the second quadrant of the hysteresis loop, wherein the demagnetization charateristics are clearly shown. The main criterion and good design practice -governing the use of the oriented material, such as that exhibiting the curve 26 is that the affect of the demagnetizing field must not act to force the shearing line 27 below the knee 28 of the curve 26.

As stated previously, the curve 25 of FIG. 6 shows the approximate demagnetization characteristic of the preferred material, which is non-oriented barium ferrite. This curve dictates that an efficient magnet will have a low magnetic length-to-area ratio. Since the characteristic is a straight line, special keepers are not necessary for magnetizing the magnet because the so-called shearing line will always dictate operation of the demragnetization curve shown. The bias strength of the magnet may be varied by magnetizing only that length L1, as shown in FIG. 3 by means of the magnetizing fixture illustrated in FIG. 5. Thus, standard size magnets may be used and may be substituted in a xed geometry to obtain varying operate and release characteristics. In a ceramic magnet of the present type, the field is very drirectional and substantially normal to the longitudinal axis of the magnet 20. Therefore, cert-ain area sections of the magnet, such as those defined by the areas Llw and Lzw, may be m-agnetized independently of one another, as indicated in FIG. 3. The area Llw has its north pole at the upper surface with relation to FIG. 4, and the poles of the area Lzw is magnetized with its south pole at the upper surface and the north pole adjacent t-he keeper 21. Another favorable characteristics of this cera-mic permanent magnet material is that its retentivity is high, and if subjected to a demagnetizing field, it will regain substantially its original magnetic characteristics when the demagnetizing Ifield disappears. The coercive force of the preferred ceramic magnet is high as indicated by the demagnetization curve 25, and therefore, the magnet will be effective in the short lengths L1 and L2. Thus, the coercive force will be high even with low length-toarea ratios.

Accordingly, the present invention further contemplates a method and apparatus for magnetizing the magnets 20 in the discrete sections defined by the areas Llw and Lzw. The fixture (see FIG. 5) used in magnetizing the magnets 20 or 22, in general, comprises two armatures or Cores 30 and 31, which are movable laterally relative to one another by means of a simple adjustment means, such as individual worm screws 32 and 33 terminating in knobs 34. The details of the worm screws and the support for the armatures should be obvious to those skilled in the art, and are not herein shown in detail. Each of the armatures 30 and 31 are provided with separate coils 35 and 36, respectively. Thus, D.C. current of, for instance, a value sufficient to produce a magnetizing field of 10,000 gauss in the air gaps, is applied to the armature through its respective coils 35 or 36 and will provide a flux path, as shown at 37, -through a block of iron or pole piece 38 and a supporting block of iron or pole piece 39. Armatures 30 and 31 are movable relative to the stationary blocks 38 and 39. A brass, or other non-magnetic, plate 40 is disposed at the upper surface of the base magnetic block 39 and is recessed to receive 4the magnets 20 or 22.

A shown in FIG. 5, rthe coils 35 and 36 are wound in such'mnner as to provide a flux path 37 as to magnetize ydiscrete 'areas Llw4 and Lzw with the north pole of area Llw being at the top surface of the magnet 20 viewed at `the left of FIG. 5, and the south pole of the top surface of thearea Lgw, as viewed at the right of FIG. 5.

`In this manner, the areas Llw and Lzw may be enlarged or decreased as desired without requiring a change in magnet size or shaving of surfaces to provide variations in cross-section or other means of varying the flux of the magnet. These areas are merely changed by moving the armatures 30 or 31 inwardly or outwardly relative to one another by turning the respective knobs 34 and their respective worm screws 32 and 33.

The magnet 20 and its keeper 21 are removed and placed adjacent a respective switching unit 10 to provide the desired biasing effect. The magnet is magnetized s0 as to operate the reed contacts 13 and 14 for normallyclosed or latched position as shown at positions CW, DW, AZ, BZ, CZ and DZ of FIG. 2, in order that they will operate within a specified ampere-turn range. Obviously,

' the degree of magnetization for latching contacts of positions AW, BW and those of columns Y and Z will be less than that required for normally-closed contacts CW and DW. The field is very directional and will affect only the particular reeds in question, and will not affect an adjacent normally-open contact, such as those of column X of FIG. 2 when the keeper 21 is used. Nor will the switches of column X be affected by the biasing action of the magnets 22 for the latching pairs of columns Y and Z.

Thus, current in the coil 12 will provide a fiux path in opposition to the magnets 20, so as to open the normallyclosed contacts of the columns W and Z and to close the normally-open contacts of the columns X and Y. In the case of the latching contacts of column Y and Z, the respective contacts will remain in the position other than the normal position upon cessation of the current supplied to the coil 12. Obviously, the present invention permits rearrangement of the switching units as desired, just as llong as the magnets affecting all contacts of a particular column are of like structure.

As far as the magnetization of the magnet is concerned, it will be appreciated that individual magnets 20 or 22 must at least match the ampere-turns ofthe coil necessary to operate a particular switch 10 from its normally-closed position, or to hold the contacts of a particular switch in latched position when current is interrupted in the coil.

Referring to the diagram of FIG. 7, it will be observed that a switch (for purposes of illustration, the switch having characteristics wherein, it will open within a range or band of 78-102 ampere-turns and will close within a band of 26-42 ampere-turns) has certain operate and release characteristics which are affected by the combined flux of the biasing magnet and the coil. The switch exhibits four sensitivity points of operation, as indicated at the zero ordinate, where no magnet is used, as in the case of a switch with a normally-open contact. The band defined by +78 and +102 ampere-turns, for example, defines a range which insures the operation of the contacts to contact-closed position, whereas the band defined by +26 and +42 ampere-turns indicates a range which insures that the contacts will be open. That is, if one follows the zero ordinate vertically from the zero abscissa, it will be observed that the normally-open contacts ofthe present preselected assortment will begin to close as the coil flux is increased in a positive direction to the value +78 ampere-turns, and all will be closed when current is supplied in an amount equal to +102 ampere-turns. As the positive current is decreased, the contacts will begin to release at +42 ampere-turns and will all be open at +26 ampere-turns.

A mirror image of the action takes place in the negative area below the zero abscissa, and as negative current is supplied to the coil, the normally-open coils will remain open until a coil flux value of -78 ampere-turns is reached and will all be closed when a value of 102 ampere-turns has been supplied thereto. Decrease of negative current supplied to the coil will permit the contacts to open between -42 and -26 ampere-turns.

In the case of providing a biasing magnet for holding contacts in normally-closed position, such as those indicated at CW and DW of FIG. 2, it will be apparent that the biasing magnet must be magnetized in areas Llw and Lzw with a flux equivalent to 102 ampere-turns or in excess of this amount when positive current is supplied. It will be necessary to provide the coil with negative current before the contacts will open.

In the matter of providing a biasing magnet for latching type contacts, such as those indicated at AW and BW and the paired switches AY, BY, CY, DY, AX, BX, CX, and DX of FIG. 2, the magnets and 22, respectively, are magnetized in areas Llw and Lzw to provide a flux equivalent to ampere-turns that fall within the operate and release ranges, such as +78 and +102 and +26 and +42, respectively, in the case of the preselected contact assortment under present discussion. Similar selection would be true for other switch operating characteristics. The present biasing magnet will then act to shift the sensitivity values to the right of the diagram of FIG. 7, and in the present case to intersect with the vertical line indicated by the dot-dash line drawn at an arbitrarily selected magnet flux value of 57 ampere-turns. This value is preferably chosen to lie intermediate the operate and release bands. Thus, it will be observed that the magnet will shift the coil iiux necessary to open the contacts from the 78-102 ampere-turns positive current band to a lesser value of approximately 22-46 positive current ampere-turn band. This shift is due to the fact that the permanent magnet acts in combination with the coil to supply the total fiux necessary to operate the contacts.

1t will be further observed that the contact open, or release band has been shifted by the magnet to negative values of approximately -12 to -28 ampere-turns. The negative contact open release band is also shifted, as is the negative contact closed or operate band, but to higher negative values of approximately -82 to -98 ampere-turns and -135 to -159 ampere-turns, respectively. Referring to the vertical dot-dash line at 57 ampere-turns of magnet flux, it will be apparent that as positive current is supplied to the coil, the contacts will close between a value of approximately +22 and +46 ampere-turns, and remain closed, or latched, even after the current is interrupted. It will take a negative current to release the contacts and of approximately -12 -to +28 ampere-turns. It -is of interest to note that the contacts will then remain open until a value of approximately +135 ampere-turns is reached. Here, there will be no latching effect upon interruption of current, as the contacts will again open as the negative current is released to the band of approximately 82-98 ampere-turns. However, the magnet may be magnetized in such manner as to latch within the negative coil flux operate band by simply reversing the magnet with respect lto the reeds 13, 14 or -to reverse the input to the coil 12.

It will ybe apparent that since the preferred ceramic magnets of the present invention lend themselves to magnetization of discrete areas and are very directional in nature, Vthat it is within the scope of this invention to supply magnets (no-t shown) which are of equivalent size as the areas Llw and Lzw, but which are independent from one lanother and separately fastened to opposite ends of a keeper (such as keeper 21). The keeper would be of ferromagnetic material lfor use with switches, such as Ithose of columns Y and Z of FIG. 2, a non-magnetic supporting bar would be used with the ceramic magnetic slugs being fastened by cement to other means to extend from opposite ends thereof (not shown).

Another important aspect of the present invention results from the use of ferrite biasing magnets, which permit automatic temperature compensation of the biased contacts. Since the coi-l ux is produced by the coil ampere-turns, and since an increase in temperature causes the coil resistance to increase, the coil flux in terms of ampere-turns will be less for a given coil voltage at a relatively 'higher temperature. This was the reason for specifying 15 volts as a minimum cold operate voltage, corresponding to a measurement on a cold coil `for of voltage operation at highest specified operating temperature. This is true for all normally open contacts.

In the case of lbiased normally closed contacts, however, the present relay takes advantage of the decrease in ias flux provided by a ferrite magnet as temperature is increased. This decrease in magnet bias fiux is therefore matched with the decrease in coil ampere-turns as the operating temperature increases due to increase in coil resistance. Thus7 the coil operating voltage will not vary appreciably with changes in temperature. This effect is only apparent in the biased contacts of the :switching units.

While this invention has been herein described by reference to specific embodiments of the same, it is intended that the protection of Letters Patent to be afforded hereby be not unnecessarily limited iby such description, the inten-tion being that such .protection extend to the full limit of the inventive advance disclosed herein as defined by the claims hereto appended.

I claim:

1. A relay comprising a group of juxtaposed sealed switching units, each including magnetically engageable contacts and being arranged in columns; a common energizing coil; biasing magnets positioned adjacent to respective ones of said units for maintaining switching units of a selected column of said group of units in biased magnetic condition, each of said magnets defining discrete, spaced apart sections of magnetized material of relatively opposite polarity, the material of said sections being further characterized -by providing a highly directional field influencing the contacts of the said respective one of said switching units; a keeper of magnetic material for a biasing magnet disposed at the side opposite of said one of said switching units; a column of normally open switching units respectively disposed adjacent `to the said keeper of the respective lbiasing magnets of said column containing the biased switching units; a pair of adjacent columns of said group of juxtaposed .switching units cornprising individual units of each of said pair of columns being matched with respective units of the adjacent paired column to provide a pair of alternatively latching switch contacts; and a biasing magnet disposed between respective pairs of latching contact switching units and comprising a magnet defining discrete, spaced apart sections of magnetized material of relatively opposite polarity, said material vbeing further characterized by providing a highly directional field influencing the contacts of the respective pairs of latching contact switching units.

2. A relay comprising a group of juxtaposed sealed switching units arranged in vcolumns and having individual operating characteristics; a common energizing coil producing `a variable magnetic field through said switching units, said group of switching units being preselected in accordance with their respective operating characteristics and disposed in the field of said -coil in an arrangement whereby the operating characteristics of said switching units substantially match the magnetic field characteristics of the area affecting the operation of a respective switching unit; biasing magnets positioned adjacent to respective ones of said units for maintaining switching units of a selected column of said group of units in biased condition, each of said Imagnets defining discrete, spaced apa-rt sections of magnetized material of relatively opposite polarity, the material of said sections being further characterized by providing a highly directional field infiuencing the contacts -of the said respective one of said switching units, a keeper of magnetic material for a biasing magnet disposed vat the side opposite of the said one of said switching units; and the other of said adjacent columns -containing no-rmally lopen switching units respectively disposed adjacent to the said keeper of the respective biasing magnets of said row of switching units.

3. A lrelay comprising a group of juxtaposed sealed switching units, each including magnetically engageable contacts and being arranged in columns, said switching units having individual operating characteristics; a common energizing coil producing a variable magnetic field through said switching units, said group of switching units being preselected in accordance with their respective operating characteristics and disposed in the iield of said coil in an arrangement whereby the operating characteristics of said switching units substantially match the magnetic field characteristics of the area affecting the operation of a respective switching unit; biasing magnets positioned adjacent to respective ones of said units `for maintaining switching units of a selected column of said group of units in biased magnetic condition, each of said magnets defining discrete, spaced apart sections of magnetized material of relatively opposite polarity, the material of said sections being further characterized by providing a highly directional field inliuencing the contacts of the said respective one of said switching units; a keeper of magnetic material for a biasing magnet disposed at the side opposite of the said `one of said switching units;

a column of normally open switching units respectively disposed adjacent to Ithe said keeper of the respective biasing magnets of said column containing the biased switching units; a pair of adjacent columns of said group of juxtaposed switching units comprising an individual unit yof each of said pair lof columns being matched with a respective unit of the adjacent paired column .to provide a pair of alternatively Ilatching switch contacts; and a biasing magnet disposed between respective pairs of latching contact switching units and comprising a magnet defining discrete, spaced .apart sections of magnetized material of relatively opposite polarity, said material being further characterized by providing ya highly directional tield inuencing the contacts of the respective pairs of latching contact switching units.

4. A relay comprising an energizing coil defining a window and producing a variable magnetic field, said field va-rying from a maximum at the periphery of the window to a minimum at the center point of the window; a group `of sealed switching units having individual operating characteristics arranged in rows and columns Within the window, each of said -switching units mounted within the window at a defined position whereat the magnetic iield of the coil substantially corresponds to the operating characteristic of the unit; and biasing magnets positioned within the window and adjacent to respective ones of aid units, each of said magnets having discrete spaced apart magnetized areas of relatively opposite polarity providing a highly directional field linfluencing the contacts of the respective `one of said switching units, the magnetic yiield strength of each magnet being proportional to the size tof the magnetized areas with the size of the magnetized areas coinciding with the operating characteristics of the respective switch to maintain said switch in the predetermined desired biased condition.

5. A relay comprising a group of juxtaposed sealed switching units arranged in columns and having individual operating characteristics; `a common energizing coil producing a variable magnetic field through said switching units, said group of switching units being preselected in accordance with their respective operating characteristics and disposed in the field of said coil in an arrangement whereby the operating characteristics of said switching units substantially match the magnetic field characteristics of the area affecting the operation of a respective switching unit; a tirst set of biasing magnets positioned adjacent to respective ones of said units for maintaining switching units of a selected column of said grou-p of units in biased condition, each of said magnets defining discrete, spaced apart sections of magnetized material of relatively opposite polarity, the material of said sections being further characterized by providing a highly directional field infiuencing the contacts of the said respective one of said switching units; a keeper of magnetic material for a biasing magnet disposed at the side opposite of the said one of said switching units; and the other of said adjacent columns containing normally open switching units biased in closed condition by a second set of -biasing magnets having opposite polarity to said first biasing magnets.

References Cited by the Examiner UNITED STATES PATENTS 1,460,759 7/1923 Kuhn-Frei 317--203 1,849,085 3/1932 Haskins `317203 2,075,504 3/1937 Chegwidden et al. 317-203 2,406,008 8/1946 E-llwood et al. 29-155.5 2,855,017 10/1958 Pollard 200-#87 2,889,424 6/1959 Glore et al. 200-87 2,902,558 9/1959 Peek 200-87 2,925,646 2/1960 Walsh 29-155.5 3,015,707 1/1962 Perreault 200-87 3,020,369 2/1962 Jacobson 200-87 3,026,390 3/1962 Koda ZOO-104 3,060,291 10/1962 Cla-re `200-104 3,114,019 12/1963 Koda 200--87 OTHER REFERENCES Bunn, J. W., and Harrington, J.: Ceramic Permanent Magnets, in Wireless World, pages 595 to 598, December 1960.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. A RELAY COMPRISING A GROUP OF JUXTAPOSED SEALED SWITCHING UNITS, EACH INCLUDING MAGNETICALLY ENGAGEABLE CONTACTS AND BEING ARRANGED IN COLUMNS; A COMMON ENERGIZING COIL; BIASING MAGNETS POSITIONED ADJACENT TO RESPECTIVE ONE OF SAID UNITS FOR MAINTAINING SWITCHING UNITS OF A SELECTED COLUMN OF SAID GROUP OF UNITS IN BAISED MAGNETIC CONDITION, EACH OF SAID MAGNETS DEFINING DISCRETE, SPACED APART SECTIONS OF MAGNETIZED MATERIAL OF RELATIVELY OPPOSITE POLARITY, THE MATERIAL OF SAID SECTIONS BEING FURTHER CHARACTERIZED BY PROVIDING A HIGHLY DIRECTIONAL FIELD INFLUENCING THE CONTACTS OF THE SAID RESPECTIVE ONE OF SAID SWITCHING UNITS; A KEEPER OF MAGNETIC MATERIAL FOR A BIASING MAGNET DISPOSED AT THE SIDE OPPOSITE OF SAID ONE OF SAID SWITCHING UNITS; A COLUMN OF NORMALLY OPEN SWITCHING UNITS RESPECTIVELY DISPOSED ADJACENT TO THE SAID KEEPER OF THE RESPECTIVE BIASING MAGNETS OF SAID COLUMN CONTAINING THE BIASED SWITCHING UNITS; A PAIR OF ADJACENT COLUMNS OF SAID GROUP OF JUXTAPOSED SWITCHING UNITS COMPRISING INDIVIDUAL UNITS OF EACH OF SAID PAIR OF COLUMNS BEING MATCHED WITH RESPECTIVE UNITS OF THE ADJACENT PAIRED COLUMN TO PROVIDE A PAIR OF ALTERNATIVELY LATCHING SWITCH CONTACTS; AND A BIASING MAGNET DISPOSED BETWEEN RESPECTIVE PAIRS OF LATCHING CONTACT SWITCHING UNITS AND COMPRISING A MAGNET DEFINING DISCRETE, SPACED APART SECTIONS OF MAGNETIZED MATERIAL OF RELATIVELY OPPOSITE POLARITY, SAID MATERIAL BEING FURTHER CHARACTERIZED BY PROVIDING A HIGHLY DIRECTIONAL FIELD INFLUENCING THE CONTACTS OF THE RESPECTIVE PAIRS OF LATCHING CONTACT SWITCHING UNITS. 